<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="js/vue.js"></script>
</head>

<body>
    <div id="app">
        <p>{{val}}</p>
        <p>{{obj}}</p>
    </div>
    <script>
        let app = new Vue({
                el: "#app",
                data: {
                    val: '简单对象初始值',
                    obj: {
                        name: "复杂对象name",
                        value: "复杂对象value"
                    }
                },
                watch: {
                    val: function (newval, oldval) {
                        console.log(newval, oldval);
                        console.log(this.val);
                    },
                    obj: {
                        deep: true,
                        handler: function (new_val, old_val) {
                            console.log(new_val, old_val);
                        }
                    }
                }
            })
    </script>
</body>

</html>